2 Istituto Italiano di Speleologia - Via Zamboni, 67 - BOLOGNA, ITALY0039 051 2094547, [email protected]
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Izvle~ek UDK: 556.34
Franco Cucchi & Paolo Forti & Enrico Marinetti & Luca Zini: Nova hidrogeolo{ka spoznanja s Krasa
Razumevanje kra{kih pojavov in razvoj hidrogeolo{kega modela, ki bi bil uporaben povsod na razvitemkrasu, bi bilo splo{no koristno. Kras, ki je æe razmeroma dobro raziskan in poznan, je lahko idelano podro~jeza multidisciplinarne raziskave. Njegova geologija, hidrologija in zgodovina sta predmet raziskav æe od 16.stoletja dalje. Dandanes kontinuirni monitoring podzemeljskih voda, digitalni model reliefa, odkritje inraziskava nekaterih novih jam je omogo~ilo izdelavo karte ranljivosti. Na podlagi izsledkov teh odkritijpredlagajo avtorji sodelovanje evropskih raziskovalcev pri razvoju hidrodinami~nega modela najbolj znanegakra{kega predela na svetu, to je klasi~nega Krasa.Klju~ne besede: zakrasevanje, hidrogeologija, ranljivost vodonosnika, Kras, Italija, Slovenija.
Abstract UDC: 556.34
Franco Cucchi & Paolo Forti & Enrico Marinetti & Luca Zini: Recent developments in knowledge ofthe hydrogeology of the Classical Karst
The Classical Karst may well be the best area for polythematic researches. It would be useful to understandkarst phenomena and create a hydrogeological model valid for all mature karst. The Karst area is quite wellstudied and known. The geology, hydrology and its history have been studied since the 16th century. Nowa-days the continuous monitoring of hypogean waters, the elaboration of a Digital Elevation Model, the discov-ery of some new caves and their study has permited the processing of the vulnerability map. On the basis ofthe results of all of these researches, we propose activating a co-operation between European researchers todevelop hydrodynamic models of the most well known karst in the world: the Classical Karst.Key words: karstification, hydrogeology, aquifers vulnerability, Karst, Italy, Slovenia.
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INTRODUCTION
The problem of obtaining full knowledge of a karst area and of its evolution may be solvedonly on the basis of interdisciplinary and polythematic studies. In fact the detailed analysis of akarst area requires the co-operation of many scientists from different fields and the acquisition ofplenty of data.
Detailed knowledge of epigean and hypogean karst morphologies and their evolution in time isthe single method by which karst water resources may be defined in terms of quantity and qualityand how their intrinsic vulnerability may be assessed in order to plan for their correct exploitation.
Jakucs was the first to point out the complexity of karst (Jakucs, 1977), and his sketch, withseveral different disciplines that interfere with each other in driving the evolution of karstmorphologies in a given area, is well known world-wide (Fig. 1). Even if most karst researchers areaware of Jakucs’s sketch, very few apply it; in fact, most of karst research is monothematic or atleast bi- or trithematic, never complex.
Absolutely rare are polythematic researches; among them are those performed in Sicily andAbruzzo by Italian researchers (Agnesi, Macaluso, 1989; Burri, 1994) and in the Slovak Ore Moun-tains (Western Carpathians) by Slovakian scientist (Novotný, Tulis, 1989).
Fig. 1: Jakucs sketch (rendition): disciplines which help us to understand Karst phenomena.Sl. 1: Discipline, ki pripomorejo k razumevanju kra{kih pojavov (prerisano iz Jakucs, 1977).
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This partially depends upon the attitude of cavers, who rarely have good relationships withanybody outside their communities. But the same behaviour may be observed, for example, alsoamong biospeleologists and archaeologists, just to cite some of the scientists involved in karst; infact, they normally are not interested in sharing their observations and findings with other scien-tists.
Moreover, due to its attitude and history, a “scientific school” often privileges a peculiar topicof karst research, sometimes pretending to ignore other aspects, the data of which may conflictwith the presented results.
THE CLASSICAL KARST
The Classical Karst (Fig. 2), due to its complexity, is probably the area in which co-operationbetween different “karst schools”, and/or research teams, may produce the best results. Most of thecharacteristics of the “Classical Karst” are known from the general point of view and often even indetail.
Morphologically the dimension, the form and the relief of the whole area are well known: mapsat different scales exist. Adjacent morphologic units have been studied and Digital Elevation Mod-
els have been prepared (Fig. 3). The structural settlement, the outcropping formations and theirlithology have been investigated in detail. Many of the old and new studies should be reinterpreted
F. Cucchi & P. Forti & E. Marinetti & L. Zini: Recent developments in knowledge of the hydrogeology of the Classical Karst
Fig. 3: Digital Elevation Model of the Karst of Trieste elaborated with IDRISI using 1:5.000 maps.In white we have drawn some lineaments and linear features which we observed after analyzingaerial photos.Sl. 3: Digitalni model reliefa Træa{kega krasa izdelan s pomo~jo paketa IDRIAI na osnovi kart1:5000. Belo so vrisani prelomi in linearne oblike, dolo~ene s pomo~jo zra~nih posnetkov.
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Fig. 4: Geomorphological map from the early 20th century (After Mühlhofer, 1907).Sl. 4: Geomorfolo{ka karta z za~etka 20. stoletja (po Mühlhoferju, 1907).
Fig. 5: Relief units and structural lines (After Habi~, 1984).Sl. 5: Reliefne in “strukturnice” (po Habi~u, 1984).
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to obtain an exhaus-tive and moderngeomorphologicaloverview of the re-gion, while dating ofthe geomorphicevents are still few orlacking (Figs. 4, 5).
Speleologicalexplorations over thelast two centurieshave supplied a lot ofcave surveys (2000in Italy and evenmore in Slovenia) -even if the accuracydiffers between them- but plenty of deepkarst phenomena arestill left to be discov-ered and explored.Moreover, almostnone of the exploredcaves have beenstudied from theg e o l o g i c a l ,geomorphologicaland sediment-ological point ofview (Lazzaro JerkoCave, TrebicianoAbyss, PadricianoCave - in Italy -,Postojna Cave,Kacna Jama Cave,Skocjanske Cave - inSlovenja).
On the otherhand the climate iswell known thanksto several active me-teorological stationsinside and outsidethe caves since dec-
Fig. 6: Hydrogeological map of Istria: 1 - limestones (very permeable);2-Interbedded limestones and dolomites, marly limestones and lime (partlyless permeable); 3 - Flysch and terra rossa (impermeable deposits); 4 -sands, gravels and clays (variations of vertical and lateral permeability);5 - normal and reverse fault; 6 - karst spring; 7 - coastal spring; 8 - well;9 - sink-hole; 10 - proved underground connection; 11 - assumed under-ground connection; 12 - line of cross-section; (After Urumovi} et al., 1997).Sl. 6: Hidrogeolo{ka karta Istre: 1 -apnenci (zelo prepustni); 2 -menjavanjeapnencev in dolomitov, lapornih apnencev in krede (deloma slab{eprepustne); 3 - fli{ in terra rosa (neprepustni nanosi); 4 - peski, prod ingline (vertikalno in lateralno spremenljiva prepustnost); 5 - normalni inreverzni prelom; 6 - kra{ki izvir; 7 - priobalni izvir; 8 - vodnjak; 9 - vrta~a;10 - dokazane podzemne povezave; 11 - predpostavljene podzemnepovezave; 12 - prerez (po UrumoviÊu s sod., 1997).
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Fig. 7: A comprehensive hydrogeological map of Karst (After Novak 1993): 1 - karst fissureaquifer; 2 - less permeable dolomite; 3 - intergranular aquifer; 4 - impermeable beds; 5 - spring;6 - smaller spring; 7 - pumping station; 8 - underground connection determined by water tracingtest; 9 - presumed underground flow of the Notranjska Reka; 10 - sinking stream; 11 - superficialstream; 12 - place with precipitation station; 13 - settlement; 14 cave with permanent stream;15 - state border.Sl. 7: Podrobna hidrogeolo{ka karta Krasa (po Novaku, 1993): 1 - kra{ki razpoklinski vodonosnik;2 - manj prepustni dolomit; 3 - intergranularni vodonosnik; 4 - neprepustne plasti; 5 - izvir;6 - manj{i izvir; 7 - ~rpalna postaja; 8 - podzemna povezava dolo~ena s sledilnim poskusom;9 - predpostavljeni podzemni tok Notranjske Reke; 10 - ponikalnica; 11 - povr{inski tok;12 - padavinska postaja; 13 - naselje; 14 - jama s stalnim vodotokom; 15 - dræavna meja.
ades ago. The actual knowledge of pedology and vegetation are good even if the available thematicmaps are normally extremely simplified. Only those related to “terra rossa” and/or other paleokarstdeposits are recent and very well detailed (Lenaz et al., 1996; Zupan Hajna, 1992).
From the hydrogeological point of view the surface hydrographic network, the flow regimeand the chemical behaviour of the rivers and springs are sufficiently known (Figs. 6, 7, 8), some-times even from continuous monitoring (Kranjc, 1997; Reichert et al., 1997; UrumoviÊ et al., 1997).
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PRESENT DAY STUDIES
Perhaps today it is easier to prepare a hydrogeological model for the Classical Karst: plenty ofresearch and studies are now available, to be used as a starting point to work out such a synthesis.Among them are the several studies on speleogenesis and hypogean hydrology performed by sci-entists from Trieste (Boegan, 1938; Civita et al., 1993; Forti et al., 1978), as well as those carriedout by Slovenian and Croatian researchers on geology and geomorphology of the superficial cavi-ties and on hydrogeology (Bonacci, 1997; HabiË, 1984; HabiË et al., 1989; Mihevc et al., 1998;Jurkov{ek et al., 1996; Placer, 1981; Slabe, 1996).
The geological knowledge of the Trieste Karst from the lithological (Cucchi et al., 1987; Cucchiet al.,1989; Ulcigrai, 1977) and structural (Carulli, Cucchi, 1981) point of view has been largelyimproved in order to define the local preferential trends for cave development. Several evidencesof recent movements and structural evolution have been observed (Carulli et al., 1981; Cucchi etal., 1979).
The different “geological” geometries (lithology, structural settlement, degree of rock massfracturation) have been compared with the “speleological” ones (direction, slope, morphology ofthe hypogean voids). In particular, a very large number of experimental measurements of the inten-sity and the geometry of the rock discontinuities have been carried out (Figs. 9, 10).
Starting from aerial and satellite images and utilising the information tools now available aDigital Elevation geo-referenced Model for the whole area has been produced (Fig. 3). Most of thenatural cavities know in the area have been analysed from the point of view of the geometry and
Fig. 8: Assumed underground connection of Karst aquifer (After Timeus, 1928).Sl. 8: Predpostavljene podzemne povezave v vodonosniku Krasa (po Timeusu, 1928).
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morphology of their voids, to obtain the preferential directions for their development both in theearly stage and the mature one (Cucchi, 1975). In fact it must be stressed here that the ClassicalKarst developed over the last 8-10 millions years, and it is still developing.
Fig. 9: From the structural point of view and from karst landforms (holes, caves, dolines, etc.), theKarst of Trieste can be divided into several different areas: first row - distribution of discontinuities;second row - preferential directions of cave development; third and fourth rows - direction, lengthand number of linear features (by aerial photos); fifth row - vertical planes conditioning holes(See also Fig. 10).Sl. 9: S strukturnega in stali{~a kra{kih povr{inskih oblik (luknje, jame, vrta~e, itd.) lahko Træa{kiKras razdelimo na ve~ obmo~ij: prva vrsta - porazdelitev diskontinuitet; druga vrsta - preferen~nasmer razvoja jam; tretja in ~etrta vrsta - smer, dolæina in {tevilo linearnih struktur (iz zra~nihposnetkov); peta vrsta - navpi~ne ploskve, ki omogo~ajo nastanek lukenj (glej tudi Sl. 10).
Fig. 10: The recognized different areas: D - Duino area; A - Aurisna area; M - Monrupino area;B - Basovizza area; VR - Rosandra Valley area. Left corner: flow direction prediction rose dia-gram drawn from “tectoglyphs” - stylolites, veins, faults - following “Eraso method” (Rendition,taken from Eraso et al., 1995).Sl. 10: Razpoznavna podro~ja: D - devinsko; A - nabreæinsko; M - repenjsko; B - bazovi{ko;VR - dolina Glin{~ice. Levi vogal: diagram predvidenih smeri toka na podlagi “tektoglifov” -stilolitov, æil, prelomov po Erasovi metodi (iz Eraso et al., 1995).
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Fig 11: Classical Karst: studied and monitored caves.Sl. 11: Kras: raziskane jame in jame z monitoringom.
Thanks to all these studies it has been proven that the geologic structural characteristics are themain controlling factors in the evolution of the Karst of Trieste: in all the sectors in which the karstarea may be subdivided, the maximum strata dip and the main subvertical discontinuities are thepreferential directions for the development of the cave galleries.
Sinkholes and pits (always subvertical and extremely abundant in the area) are all normallycontrolled by a single well-defined discontinuity with a structural axis between N-S and NNE-SSW, and their genesis is by far younger than that of the draining network of phreatic tubes.
Geomorphologic surveys have shown that no surface evidence exists for faults which control-led the evolution of some caves; moreover, several collapse dolines show a far wider vertical di-mension (even if sometimes masked by subsequent collapses and infillings) than spatial (the depthto width ratio often being 10:1).
In order to reconstruct the groundwater dynamics plenty of hydrochemical and geochemicalanalyses have been performed and recently several data loggers have been placed in the area inorder to have a continuous record for the chemistry and the hydrodynamics of the karst waters(Figs. 14, 15). These data can be easily compared with rainfall, with flow regimes of the rivers(Reka, Vipava/Vipacco, SoËa/Isonzo) which feed the karst aquifer, and with the discharge of thespring complex (Cucchi et al., 1997; Flora et al., 1990; Gemiti, 1994; Gemiti, Licciardello, 1977;Krivic, 1982).
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Fig. 12: a) in the [kocjanske Cave water flows to the North-West; b) the gallery network in KaËnaCave influences the variability of the drainage direction: resultant is East to West; c) in theTrebiciano Abyss inside the horizontal deep gallery (Ce: Cenomanian Rudist limestone, Ce*:Cenomanian limestone, Al: Albian-Cenomanian dolostone) the Timavo river flows from South toNorth; d) in the flooded hypogean network of the Timavo springs the water flows from North toSSW (Ce: Cenomanian limestone).Sl. 12: a) skozi [kocjanske jame te~e voda proti SZ; b) mreæa rovov v Ka~ni jami vpliva naspreminjanje smeri odtoka: rezultanta je smer V - Z; c) skozi Labodnico te~e Timava po globokemvodoravnem rovu od J proti S (Ce: cenomanijski rudistni apnenec, Ce*: cenomanijski apnenec,Al; albijsko - cenomanijski dolomit) d) skozi potopljeno podzemno mreæo izvirov Timave te~e vodaod S proti JJZ (Ce: cenomanijski apnenec).
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Fig. 13: a) Padriciano cave is conditioned bylithologic and structural settlement (Pa:Paleocene limestone, Ce: Cenomanian Rudistlimestone); b) Lindner Cave develops alongstrata planes (Ce: Cenomanian Rudist lime-stone); d) in the Lazzaro Jerko Cave (just dis-covered) water (inside a horizontal deep gallerydeveloped in dolostone) flows from East to West.Sl. 13: a) Labodnico pogojujejo litolo{ke instrukturne zna~ilnosti podro~ja (Pa: paleocenskiapnenec, Ce: cenomanijski rudistni apnenec);b) Lindnerjeva jama je razvita vzdolæ lezikCe: cenomanijski rudistni apnenec); d) v nedavnoodkriti jami “Lazzaro Jerko” te~e voda (vglobokem vodoravnem rovu, razvitem v dolomitu)v smeri V - Z.
In fact it must pointed out that in an area of a few square kilometers the groundwater comes outin some lakes and several springs; moreover, the base level can be reached through several naturalcavities.
Continuous recording of temperature, conductivity, flow rate and base level and weekly analy-ses of the chemical behaviour for many waters are presently available thus allowing us to under-stand the hydraulic behaviours of the karst drainage and to test the hydrodynamic models pro-posed.
Moreover, the automatic instruments located in several points of the underground drainage inthe last few years supply very useful data for the definition of the water flow inside the karstnetwork.
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Fig. 14: [kocjanske Cave, Trebiciano Abyss, Timavo Springs: water conductivity and temperatureduring 1997.Sl. 14: [kocjanske jame, Labodnica, izviri Timave: prevodnost in temperatura vode v letu 1997.
Plenty of dye tracing experiments have tested the connections between the recharge areas andthe karst springs. Many other studies related to different aspects of karst hydrology and hydrogeologyhave been done in the last few years, however some important factors of the karst flows are stillunknown. The location of real drainage flows, the volumes of preferential flows, and those of adiscontinuous or diffuse nature have not yet been evaluated; the local flow directions are stillundetermined and the values for the vertical and or horizontal permeability in the differenthydrogeological situations are still unknown.
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Fig. 15: Trebiciano Abyss, Colombi Cave, Timavo Springs: water level during 1997.Sl. 15: Labodnica, jama “Colombi”, izviri Timave; gladina vode v letu 1997.
INTRINSIC VULNERABILITY
Recently maps of intrinsic vulnerability for the karst aquifer have been proposed. Aquifer vul-nerability, intrinsic or natural, is defined as the specific susceptibility of aquifer systems, in theirvarious parts and in their various geometric and hydrodynamic settings, to ingest and diffuse fluidor/and water-borne contaminants, the impact of which on the ground water quality is a function ofspace and time. The vulnerability of an underground water body is a function of a number ofparameters: hydrolithology and hydrostructure of the hydrogeological system, nature of soil andoverburden, recharge, ground water inflow-outflow processes, the physical and hydrogeochemicalprocesses that produce the natural quality of water and the attenuation of the prevailing contami-nants impacting the system.
In our researches, the SINTACS method to evaluate the aquifer’s vulnerability to pollution isapplied (Civita, De Maio; 1997). The program is based on a Parametric Point Count System model(PCSM) which has been specifically adapted to the peculiarities of karst environments and suc-cessfully tested in several of the main karst areas of Italy.
The acronym of the program comes from the initials (in Italian) of the seven parameters uti-lized in the computer algorithm: Soggiacenza (depth to groundwater), Infiltrazione efficace (net
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recharge), Non saturo (unsaturated zone), Tipo di copertura (soil characters), Acquifero (aquifertypes), Conducibilita’ idraulica (hydraulic conductivity), Superficie (slope).
The depth of the piezometric level (both for confined or unconfined aquifers) referenced to theground surface has a large significance on vulnerability because its absolute value together withthe unsaturated zone characteristics, determine the travel time (TOT) of a water-borne or fluid con-taminant and the duration of the attenuation process, in particular the oxidation process by atmos-pheric O
2.
The role that effective infiltration plays in aquifer vulnerability assessment is very significantbecause of the direct infiltration of pollutants on the one hand, and their dilution (first during thetravel through the unsaturated zone and second within the saturated zone) on the other.
Inside the unsaturated zone a four dimensional process takes place in which physical and chemicalprocesses interact to promote the contaminant attenuation. The unsaturated zone attenuation ca-pacity is assessed starting from the hydro-lithologic features (texture, mineral composition, grainsize, fracturing, karst development, etc.). A rating is assigned to the hydro-lithology of the unsatu-rated zone with the cell of the square grid as its base.
The type of overburden, and particularly of the soil, plays a very effective role in the attenua-tion process of contaminants travelling inside a hydrogeological system, and hence in aquifer vul-nerability assessment and mapping. Soil is identified as an open, three-phase, accumulator andtransformer of matter and energy sub-system which develops by physical, chemical and biologicalalteration of the bottom lithotypes and of the organic matter filling it. It is the first defence line ofthe hydrogeological system: inside the soil is where several important processes take place to en-hance the attenuation capacity.
In vulnerability assessment models the aquifer characteristics describe the processes that takeplace below the piezometric level. Before a contaminant is mixed with groundwater it has more orless lost a relevant part of its original concentration during the travel through the soil and theunsaturated thickness. Those processes are, essentially: molecular and kinematic dispersion, dilu-tion, sorption and chemical reactions between rock and contaminants.
Hydraulic conductivity represents the groundwater mobility capacity inside the saturated me-dia, and thus the mobility potential of a water-borne contaminant having a density and viscosityalmost the same as of groundwater. In the SINTACS assessment context, this parameter governs thehydraulic gradient and the equipotential flux across sections, the aquifer unit yield and flow veloc-ity toward the effluences and the tapping work marking the exposition of risk targets.
Topographic slope is an important factor in vulnerability assessment because it governs theamount of surface runoff produced, the precipitation rate and displacement velocity of water (or afluid and/or water-borne contaminant) over the equipotential surface. Moreover, the slope may bea genetic factor for the soil type and thickness, indirectly governing the attenuation potential of thehydrogeological system.
The SINTACS program calculates a numeric value for the intrinsic vulnerability which is thenconverted in % and finally subdivided into 6 vulnerability classes (Extremely High, Very High,High, Medium, Low, Very Low or Null) which are represented in a map by different colors.
We have used IDRISI for processing all the maps elaborated by SINTACS model. This GIS isvery useful for the map overlaying that is essential to obtain the vulnerability maps. It does not usea square network, normally used for cartographic processing of SINTACS, but it works in pixels.
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Fig. 16: The Intrinsic Vulnerability Map of the Italian part of the Classical Karst, processed withSINTACS (release 4) and IDRISI GIS, The map is georeferred on the Numerical Map 1:5.000 ofFriuli-Venezia Giulia Region.Sl. 16: Karta splo{ne ranljivosti italijanskega dela Krasa, izdelana s paketom SINTACS (verzija 4)in IDRISI GIS. Karta se navezuje na zemljevde 1:5.000 Furlanije - Julijske krajine.
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So it is possible to choose the best definition for the final map and follow the natural borders of thestudied area’s limits by all parameters with more accuracy: our work has a base grid of 10 m fields(Fig. 16).
KARST EVOLUTION MODEL
Practically, a hydrogeological model that fitsall the already available data has not yet beenproposed. Presently only hypotheses, or attemptsof hypotheses, exist, none of which can justifythe many self-contradictions resulting from a de-tailed analysis of the entirety of the thematic stud-ies.
Moreover, the comparison of the mineralogi-cal content of the “terre rosse” on the surface withthe cave deposits allow us to state that the re-charge came from several and not a single feed-ing basin.
Several are the blowing caves during thefloods in the Timavo river, but they are not ho-mogeneously distributed and they are not alignedalong preferential directions.
The hydrodynamics are not unambiguous:floods derived from similar inputs may show
Fig. 17: Examples of hydrogeologic models(After Badino, 1995 and Mohrlok et al., 1997).Sl. 17: Primeri hidrogeolo{kih modelov (poBadino, 1995, in Mohrlok et al., 1997).
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different delay times and different chemical behaviour, while identical flood diagrams may corre-spond to different climatic and hydrologic conditions.
There are many other incongruences which should be considered globally: a modernhydrogeological model for the Classical Karst may only result by strict cooperation between all thescientific teams presently working on it. If this will happen then the Classical Karst will becomethe new symbolic karst area, where scientists from all over Europe will test their hypotheses andmodels (Fig. 17) (Badino, 1995; Birsoy, 1997; Bodin, Razack, 1997; Dreybrodt, Siemers; 1997;Pulido-Bosch et al., 1993). It should become the first area in which a general methodology to studykarst areas in a multidisciplinary manner can be defined in order to achieve hydrogeological mod-els suitable for a safe exploitation of karst water resources.
The hydrogeological model is in fact absolutely needed not only to enhance the scientific knowl-edge on karst phenomena, but also to make the exploitation of hosted resources easier. However,modelling the hydrogeological behaviour of an area is extremely difficult due to the very highnumber of independent parameters which must be considered simultaneously. This is the challengewe have to face in Classical Karst.
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Popolno razumevanje krasa in njegovega razvoja je mogo~e le na osnovi inter- inmultidisciplinarnega pristopa. Detajlna analiza kra{kega podro~ja je moæna le ob sodelovanjuraziskovalcev z razli~nih podro~ij in na osnovi analize velikega {tevila podatkov. Kakovost inkoli~ino kra{ke vode ter ranljivost kra{kih vodonosnikov lahko definiramo le, ~e podrobno poznamopovr{insko in podzemeljsko morfologijo kra{kega podro~ja in njegov razvoj. To je tudi osnova zapravilno izkori{~anje kra{kih voda.
Jakucs je prvi izpostavil kompleksnost krasa in njegov diagram prepletanja disciplin, potrebnihza {tudij razvoja kra{ke morfologije na nekem podro~ju, je splo{no poznan. ̂ eprav ga pozna ve~inakrasoslovcev, ga le malokdo uporablja; {e vedno je pristop k raziskavam krasa predvsemmonotematski, morda bi- ali tridisciplinaren, a redko zares kompleksen. Pogosto se ne upo{tevajodolo~eni aspekti obravnavane tematike ali podatki, ki so v nasprotju s pri~akovanimi rezultati.Redke resni~no politematskek raziskave so bile opravljene na Siciliji, v Abruzzih in v ZahodnihKarpatih na Slova{kem.
Podro~je klasi~nega Krasa je tisto, na katerem sodelovanje med razli~nimi krasoslovnimi {olamizaradi njegove kompleksnosti lahko da najbolj{e rezultate. V splo{nem so znane vse njegovezna~ilnosti, v precej{nji meri pa poznamo tudi detajle, npr. morfologijo, obstajajo podrobne kartepodro~ja ipd. Raziskane so tudi sosednje morfolo{ke enote, tako da je izdelan digitalni modelreliefa. Prav tako so podrobno dolo~ene strukturne enote in litologija formacij, ki izdanjajo. Pripodrobnem pregledu geomorfologije so potrebne nekatere nove razlage obstoje~ih podatkov, medtemko je datacija posameznih dogodkov pogosto {e vedno pomanjkljiva.
V zadnjih 200 letih je bilo objavljenih preko 2000 speleolo{kih raziskav v Italiji in pribliænotoliko v Sloveniji, od katerih vse morda niso zanesljive. Kljub temu pa je veliko kra{kih pojavovgloboko pod povr{ino {e vedno neznanih oziroma neraziskanih. Le malo jam je bilo podrobnoopisanih tudi z geolo{kega, geomorfolo{kega ali sedimentolo{kega stali{~a.
O Krasu je razmeroma veliko meteorolo{kih podatkov, zahvaljujo~ gosti mreæi meteorolo{kihopazovalnic. Tudi pedolo{ki podatki in podatki o vegetaciji so zadovoljivi, ~eprav so mnoge tematskekarte precej poenostavljene. Novej{e resni~no detajlne karte obravnavajo terra roso in/ali drugepaleokra{ke sedimente. Povr{inska hidrografska mreæa, tokovni reæimi in kemizem voda so dobropoznani, ~eprav pogosto ni na razpolago kontinuiranega monitoringa. V zadnjih letih so na ve~mestih v podzemlju name{~ene avtomatske merilne postaje, ki dajejo pomembne podtke za raziskavepodzemnih vodnih tokov. Opravljeni so bili mnogi sledilni poskusi, s katerimi so raziskovalipovezave med zbirnimi podro~ji in kra{kimi izviri. V zadnjih nekaj letih so bile opravljene tudi{tevilne druge {tudije, ki so obravnavale razli~ne aspekte krasa. Vendar so nekateri dejavniki,
F. Cucchi & P. Forti & E. Marinetti & L. Zini: Recent developments in knowledge of the hydrogeology of the Classical Karst
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pomembni za hidrologijo krasa, {e vedno nedolo~eni, npr. lokacija dejanske drenaæe, volumenpreferen~nih tokov, ob~asni in difuzni tok. Lokalne smeri tokov {e vedno niso dolo~ene, tudivertikalna in horizontalna prepustnost kamnin v razli~nih hidrogeolo{kih pogojih {e ni znana.
V pripravi so karte splo{ne ranljivosti kra{kih vodonosnikov. Ker pa {e vedno niso definiranepreferen~ne smeri tokov , tudi lateralna in vertikalna prevodnost nasi~enih in nenasi~enih con kra{kihvodonosnikov ni znana. Tudi prakti~ni hidrogeolo{ki model, ki bi upo{teval vse parametre, s katerimibi lahko zadovoljivo opisali do zdaj zbrane eksperimentalne podatke, {e ni razvit. Obstajajo samohipoteze, nobena od njih pa ne pojasnjuje nekaterih nasprotujo~ih si dejstev, ki izhajajo iz tematskorazli~nih {tudij. ^e na primeru [kocjanskih jam uporabimo metodo “smeri razvoja jam” ali metodo“napoved smeri toka” po Erasu, dobimo povsem drugo teoreti~no smer toka od dejanske, ki potekaod JV proti SZ, t.j. od [kocjana proti izvirom Timave.
V jamah z aktivnim tokom ([kocjanske jame, Ka~na jama, Labodnica, izviri Timave) ima tapovsem drugo smer kot pa je regionalna smer tokov na tem podro~ju. Primerjava mineralne sestavejamskih sedimentov s povr{insko rde~o prstjo kaæe, da se voda v jame steka z ve~ razli~nih podro~ij.
Ob nara{~anju podzemeljske Reke pri~no delovati {tevilni dihalniki, vendar niso enakomernorazporejeni niti niso locirani vzdolæ preferen~nih smeri. Hidrodinamika ni enozna~na: visoke vodeiz istega vira imajo lahko razli~no zakasnitev in razli~ne kemijske zna~ilnosti, medtem ko identi~nidiagrami visoke vode lahko ustrezajo razli~nim klimatskim in hidrolo{kim pogojem.
Obstaja {e ve~ navideznih nasprotij, ki bi jih bilo treba obravnavati celovito: sodobnihidrogeolo{ki model Krasa je mogo~e izdelati le ob dosledni povezavi raziskovalnih skupin, kidelajo na tem podro~ju. ^e naj Kras postane modelno obmo~je za kra{ke terene, na katerem biraziskovalci iz vse Evrope testirali svoje hipoteze in modele, potem mora biti tudi prvo podro~je,na katerem bo definiran multidisciplinarni pristop k izdelavi hidrolo{kega modela, ki bo sluæil zavarno izkori{~anje kra{kih vodnih zalog. Hidrogeolo{ki model je dejansko potreben za bolj{epoznavanje kra{kih pojavov, pa tudi za laæje in bolj{e izkori{~anje kra{kih virov. Modeliranjehidrogeologije nekega podro~ja je izjemno zahtevno zaradi velikega {tevila neodvisnih spremenljivk,ki jih je treba so~asno upo{tevati. Prav to pa je izziv klasi~nega Krasa.
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